DEVELOPMENT AND EVALUATION OF A CARBONATED LIQUID
WHEY BASED BEVERAGE SYSTEM
BY
EMILY J. FREDERICK
A FINAL REPORT
SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS
FOR THE COLLEGE OF AGRICULTURE HONORS PROGRAM
PROJECT ADVISOR: DR. FADI M. ARAMOUNI
FOOD SCIENCE INSTITUTE
COLLEGE OF AGRICULTURE
KANSAS STATE UNIVERSITY
MANHATTAN, KS
MAY 2007
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ABSTRACT
The objective of this project was to develop a value-added beverage that utilizes
unprocessed liquid whey as a byproduct of cheese manufacture. Liquid whey
accounts for up to ninety percent of the yield during cheese making and has
historically been considered a waste product. As legal and environmentally
friendly whey disposal options dwindle, alternative utilization strategies for the
liquid whey must be developed. Further processing of whey, such as drying,
creates a potential financial burden on small cheese producers. Considering the
proteins found in whey are associated with known health benefits, the nutrient
laden, unprocessed liquid whey is an ideal base for a wholesome beverage. With
the advantage of added whey protein and the appeal of carbonation, the resulting
carbonated protein beverage would make a unique and successful addition to the
growing health beverage sector.
A carbonated, liquid whey based beverage system was developed, keeping in
mind the technological and financial capabilities of a small producer. The product
was evaluated based on physical, microbiological, and sensory characteristics.
With minor formulation changes, this beverage could realistically and
competitively exist in today’s marketplace.
INTRODUCTION:
Whey is the yellow, watery liquid that separates from the curd during the cheese
making process (Smithers et al., 1996) and contains nearly half of all solids found
in whole milk (Chandan et al., 1982). It is estimated that during the production of
one pound of cheese, approximately nine pounds of whey are produced
(Anonymous, 2002). At one time, this whey was viewed as nothing more than a
waste product. Cheese processors disposed of whey down drains until tightened
environmental regulations made the dumping process illegal and expensive
(Frank, 2001). Other disposal mechanisms included the discharge of whey into
local waterways, the ocean, or as a component in animal feed (Smithers et al.,
1996). Additionally, some whey has also been used as nutrient-laden soil
enrichment in a process called landspreading. As landspreading restrictions and
water treatment facility regulations continue to tighten over the next few years,
cheese manufacturers will be forced to find alternative methods for disposing of
or utilizing whey (Casper et al., 1999). Drying technologies are available for
processing liquid whey into whey protein isolates and concentrates for an
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abundance of applications, but the energy needs alone can overwhelm small
cheese producers. Equipment costs can also be prohibitive. An alternative
solution for liquid whey disposal is needed.
In order to provide assistance to Alma Creamery, LLC., the Kansas Department
of Commerce, a funding source for this research, has requested the development
of a value-added beverage that utilizes unprocessed cheese whey as an
alternative to disposing of the whey into the environment. As an extension of
previous graduate research by Raymond Kassatly (Kansas State University,
Manhattan, KS), the proposed beverage would continue to be formulated with a
liquid whey base, but with the added value of carbonation.
Whey Proteins
Whey protein is a protein fraction obtained from cow’s milk. Milk contains two
major protein fractions, including casein, which provides about 80% by weight of
the total protein, and whey protein, which provides about 20% by weight of the
total protein (Whey, 2001). While its concentration in milk is not significant, whey
protein contains all of the essential amino acids, and therefore, is a high quality,
“complete source” of protein (Whey, 2001). More specifically, whey proteins are a
rich source of branched chain amino acids (BCAAs), containing the highest
known levels of any natural food source (Miraglio, 2004). BCAAs are important
for athletes, since, unlike the other essential amino acids, they are metabolized
directly into muscle tissue and are the first amino acids used during periods of
exercise and resistance training. While these nutritional characteristics would
benefit athletes, whey protein has the potential to extend its advantages to an
average consumer. In a clinical trial presented in 2006 by the United States
Department of Agriculture (USDA) researchers found that those “consuming
supplemental whey protein weighed less and put on less body fat compared to
individuals who consumed a calorie-equivalent carbohydrate supplement”
(Anonymous, 2006).
From a functional perspective, dried whey protein is appropriate for beverage
formulation in that it has a fresh, neutral taste and, therefore, can be included in
other foods without adversely affecting the taste. Any flavor that is imparted from
the whey protein lends itself well to citrus and fruit-flavored drinks. It is, however,
important to consider that unprocessed liquid cheese whey is regarded as nearly
unpalatable in its original, unprocessed form. In addition to flavor attributes, whey
proteins function in an array of beverages due to their solubility over a wide pH
range. The ideal pH of a proposed whey protein beverage would either be far
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above or below the isoelectric point (pI) of whey proteins, which is 4.6. If the
beverage is formulated at or near this point, the whey proteins will precipitate and
beverage quality and acceptability will suffer.
Commercial Whey Protein Products
Given the advantages of whey protein, it has become a popular source of
nutrition in a variety of forms: whey protein supplement bars, whey protein
concentrates, whey protein isolates, and whey protein beverages. According to
Mintel International’s Global New Products Database (GNPD), 1,763 products in
the United States and 6,435 worldwide were introduced with whey ingredients in
2005 (Gottschalk, 2006). These products require that the whey be processed
from its original form through drying technologies, ultrafiltration, and/or hydrolysis
treatments. The intent of this research was to utilize the unprocessed cheese
whey as the liquid base for a beverage. A broad and informal market evaluation
of the current whey protein beverage sector shows no evidence of such a
product.
MATERIALS AND METHODS:
Preliminary Studies
Preliminary experimental work was done with a variety of flavors, thickeners, and
sweeteners. Extensive effort was made to combine natural and artificial flavors
with protein masking agents. A final combination of fruit flavors, including
raspberry, banana, and pineapple was chosen. Due to the fact that the coloring
agent was dispersed in the main flavor ingredients, a creamy fuschia color
resulted in the product. Various thickeners were applied to the beverage system,
such as gum arabic, carboxymethyl cellulose (CMC), and pectin/xanthan gum
blends. The use of these ingredients ultimately resulted in unfavorable results,
including gritty mouthfeel and bitter flavor notes. Therefore, the use of
hydrocolloids as suspension and stabilization agents in the final product was
avoided in this first phase of research. Finally, experimentation with the use of
various sweeteners was carried out. Fructose, acesulfame-K, high fructose corn
syrup, and white grape juice concentrate were all considered, with the final
choice being white grape juice concentrate because of its consumer acceptability
and appropriate sweetening/flavoring capability.
In order to become better acquainted with the provided pilot plant-scale
carbonation equipment, numerous practice attempts were made with water,
unprocessed liquid whey, and preliminary formulations of the beverage. In doing
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so, issues with protein foaming, consistency in carbonation levels, and
equipment maintenance issues were discovered.
Through trial and error, coupled with continued informal sensory evaluation by a
panel of food scientists, a final acceptable beverage formula was developed, as
shown by the formulation in Table 1.
Table 1.
Ingredient
Amount (% by weight)
Sweet Liquid Whey
85.90
80% Whey Protein Concentrate
3.97
Protein Masking Agent
0.10
White Grape Juice Concentrate
8.94
Citric Acid, anhydrous
0.26
Natural & Artificial Flavoring
0.78
Anti-Foaming Agent
0.05
Processing
Frozen liquid cheddar cheese whey was received from a commercial cheese
manufacturing facility (Alma, KS). The liquid whey was kept frozen at -20oC until
use (within 3 months). The frozen whey was thawed at refrigeration temperatures
and then filtered through a sieve to remove any physical traces of the cheese
manufacturing process. The remaining ingredients were added to the whey in the
following order: whey protein concentrate, protein masking agent, white grape
juice concentrate, citric acid, flavors, and an anti foaming agent. With continuous
stirring, the mixture was heated and pasteurized at 73 oC for 20 seconds to
remove all pathogenic microorganisms, as well as some yeasts or molds. The
heat-treated beverage was placed in a cooler to facilitate immediate chilling and
continued to chill overnight.
The beverage was carbonated using a Series 9000 Zahm Pilot Plant Filter,
Carbonator, and Filler (Zahm and Nagel, Holland, NY). Prior to carbonation, the
tank and fill lines were sanitized with a 200ppm chlorine bleach solution in
potable water. The chilled beverage mix was placed into the sanitized tank which
was subsequently placed into a aluminum pail of salted ice water. The mixture
was chilled to 5oC in order to facilitate better dissolution of carbon dioxide in the
beverage. Following the manufacturer’s directions, the beverage was carbonated
at a pressure of 25 pounds per square inch (psi).
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Once carbonated, the beverage was filled into 12 ounce glass bottles and
capped with a metal lid. The filled bottles were then immediately stored at 4 oC
and held for subsequent evaluation.
pH
The pH values were measured using a Fisher Accument® Model AP 63 pH
meter with a pH/Automatic Temperature Compensation (ATC) combination
electrode calibrated at pH 7.0. Measurements of pH were taken on the
uncarbonated and carbonated samples in duplicates and an average was
calculated.
Brix
Soluble solids content was measured using an Abbe Mark2 Refractometer
(Cambridge Instruments Inc., Buffalo, NY). Samples were loaded into the
machine and viewed through the eyepiece for adjustment until the color zone
separation matched the cross-hair line. The % Brix was then read directly from
the display and recorded. Duplicate measurements were taken from both the
uncarbonated and carbonated samples and then averaged.
Color
Color measurements were made using a HunterLab MiniScan™ MS/S-4000S
spectrocolorimeter (Hunter Associates Laboratory, Inc., Reston, VA) to determine
the L*, a*, and b* values of the uncarbonated and carbonated samples. The
MiniScan™ was standardized with a black light trap and white color tile before
the first sample was measured. Samples were placed in a polysterene clear cup
with a plastic ring inside holding the sample in place and then covered with a
black cup to prevent light from reflecting and interfering with the measurement.
L*, a*, and b* values were measured three times and then averaged. Duplicates
were made with all samples. L* represents the whiteness of a sample, where 100
represents white and 0 is black. A positive ‘a*’ value indicates redness, and a
negative ‘a*’ value indicates greenness. A positive ‘b*’ value represents
yellowness and a negative ‘b*’ value represents blueness (Hunter, 1996).
Carbonation Level
Volumes of carbon dioxide in the carbonated beverage were measured using a
Series 6000 Zahm Model D.T. Piercing Device (Zahm and Nagel, Holland, NY).
The full bottle of carbonated beverage was inverted and subsequently pierced
with the device. The pressure inside the bottle was measured directly from the
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accompanying gauge. The device’s thermometer was inserted into the product
and the temperature was read directly. Based on a table provided with the
carbonation equipment, the total volume of carbon dioxide dissolved in the
product was calculated. Duplicate measurements were taken from the
carbonated sample and then averaged.
Microbiological
AOAC methods 986.33 and 989.10 for dairy products were used to detect the
presence of aerobic bacteria in both the uncarbonated and the carbonated
beverage products. One milliliter of the product, diluted to 1:10 and 1:100 with
serial dilutions, was plated on 3M™ Petrifilm™ (Aerobic Count Plates, 3M, MN)
and then incubated at 32°C ± 1°C for 48h ± 3h. AOAC 997.02 method was used
to detect the presence of yeast and mold in both the uncarbonated and
carbonated beverage products. One milliliter of the product, using the previously
stated serial dilutions, was plated using 3M™ Petrifilm™ (Yeast and Mold Plates,
3M, MN) and incubated at 20-25°C for 3 to 5 days. AOAC method 983.25 was
used to detect the presence of total coliforms in both the uncarbonated and
carbonated beverage products. One milliliter of the product, using the previously
stated serial dilutions, was plated on 3M™ Petrifilm™ (ECC Plates, 3M, MN) and
then incubated at 32°C ± 1°C for 48h ± 3h.
Sensory
Faculty, staff and students participated in an informal sensory study. Consumers
(n=35) were asked to fill out a questionnaire regarding age, gender, and
beverage consumption habits. An informed consent form listing ingredients and
potential ingredients in the beverage was signed by each participant prior to
tasting. Consumers were asked to evaluate the sample for overall liking,
appearance, mouthfeel, flavor, and sweetness on a 9-point hedonic scale
anchored on the left by 1 (“dislike extremely”) and on the right by 9 (“like
extremely”).
Nutrition Labeling
The basic nutritional content was determined for the carbonated beverage using
the Genesis R&D labeling program (ESHA Research, Salem, OR). The serving
size was reported by FDA (21 CFR 101.9 (b)).
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RESULTS AND DISCUSSION:
pH
The pH measurements for the uncarbonated and the carbonated samples were
4.24 and 4.13, respectively. This decrease in pH can be explained by the
conversion of carbon dioxide into carbonic acid. The presence of the carbonic
acid increases the concentration of hydrogen ions in solution, thus lowering the
pH. A final pH of 4.13 is ideal for this beverage system as it falls far enough away
from the previously mentioned isoelectric point of whey proteins and will thus
prevent undesirable protein precipitation.
Brix
The °Brix for the uncarbonated and the carbonated samples was 13.9 and 15,
respectively, as shown in Table 2. These data are indicative of the amount of
sugar and/or soluble solids in the product, and therefore, suggestive of the
sweetness of the beverage.
Color
According to the results for the color readings shown in Table 2, the
uncarbonated sample appears darker in color, as indicated by a lower L* value.
The higher a* value in the carbonated sample indicates that it is more red. Not
much difference is seen in the b* values of the two samples, indicating that they
have similar yellowness.
Carbonation Level
After carbonation, the resulting product contained an average of 2.2 volumes of
carbon dioxide. This amount of gas was suggestive of the final mouthfeel of the
product, ranging from “sparkling” (too little carbonation) to “foamy” (too much
carbonation). The use of the pilot carbonation equipment made it difficult to
control the final concentration of carbon dioxide. The final volume of CO2 was
contingent upon the accuracy and consistency of the original carbonation
pressure, the temperature of the bottle, and the rapidity of the bottle capping.
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Table 2. Physical Analyses of Uncarbonated and Carbonated Beverage
Physical Property
Pre-Carbonation
Post-Carbonation
pH
4.24
4.13
Brix (% Soluble Solids)
13.9
15.0
Color
L*: 23.72
L*: 26.98
a*: 8.26
a*: 11.11
b*: 3.07
b*: 3.56
Carbonation
N/A
Temperature: 7°C
Gage Pressure (psi):10
Volumes of CO2 : 2.2
Microbiological
It was the microbial testing that revealed a setback in the realistic development of
the carbonated liquid whey beverage. According to Table 3, the pasteurization
process for the uncarbonated sample proved to be efficient. The carbonated
sample, however, showed results that were unexpectedly high in all three
microbial sampling tests. It was concluded that while appropriate sanitizing
measures were taken in preparing the tank and fill lines, the pilot level of
production is not adequate to produce a carbonated protein beverage with an
adequate shelf-life to commercialize the product. Alternative post-processing
pasteurization techniques are limited, as heating post-carbonation could greatly
diminish the dissolved volumes of carbon dioxide in the product.
Table 3. Microbial Results for Uncarbonated and Carbonated Beverage
Type of Analysis
Uncarbonated Carbonated
Aerobic Plate Count (APC) <10 CFU/mL
300 CFU/mL
Yeast and Mold (YM)
< 10 CFU/mL 8000 CFU/mL
E. coli / Coliform (ECC)
30 CFU/mL
300 CFU/mL
Sensory
Participants ranged in age from 18 to 50 years old. There were fewer males that
participated than females, with 23 females and 12 males. 100 percent of the
respondents had at least some college education. Approximately 43% of
participants claimed to “never” consume protein beverages, and only 5% claimed
to consume protein beverages once per week. Approximately 71% of
respondents consume carbonated beverages anywhere from everyday to once a
week. Mean values for overall acceptability, appearance, flavor, sweetness and
mouthfeel are given in Table 4. Based on a 9 point hedonic scale, the average
score for overall acceptability was a 5.74. Using the scale provided to panelists,
the product should average a ‘6’ or above before being launched into the market.
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As an extension of the evaluation, more consumers would be surveyed and
current whey protein beverages would be compared to the test product. A trained
panel may be needed to narrow in on what attributes are disliked in the product
and what consumers are looking for.
Table 4. Sensory Evaluation of Carbonated Beverage
Category
Score
Overall Acceptability 5.74 ± 1.6
Appearance
6.74 ± 1.2
Flavor
5.44 ± 1.7
Sweetness
5.97 ± 1.4
Mouthfeel
5.35 ± 1.6
Nutritional Labeling
After input of the beverage formula into the Genesis R&D computer database,
the following nutritional label resulted:
Figure 1. Nutritional Label
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CONCLUSION:
A carbonated liquid whey based beverage system was developed and prepared
as an alternative solution to both ground disposal and burdensome and
expensive drying of liquid whey. The results indicated the feasibility of such a
system, although challenges remain. Other factors that may be of interest in
continued studies include evaluation of shelf stability, variation in flavors and
colors, effective use of hydrocolloids for particle suspension, and alternative postprocessing pasteurization techniques. Economic feasibility and marketing
research will also need to be performed to ensure the success of the product.
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